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Scattering of plane SH w.ves by a circular-arc hill w.th a circular tunnel

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Acta Seismologica Sinica(English Edition) 2004年第5期17卷 549-563页

作者： LIANG Jian-w.n(梁建文) LUO Hao(罗昊) vincent w. lee Department of Civil Engineering Tianjin UniversityTianjin300072China Department of Civil EngineeringUniversity of Southern CaliforniaLos AngelesCA 90089-2531U.S.A. Department of Civil EngineeringUniversity of Southern CaliforniaLos AngelesCA90089-2531U.S.A.

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关键词： hill tunnel scattering plane SH w.ves analytical solution

Out-of-plane (SH) soil-structure interaction： a shear w.ll w.th rigid and flexible ring foundation

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Earthquake Science 2016年第1期29卷 45-55页

作者： Thang Le vincent w. lee Hao Luo Sonny Astani Civil & Environmental Engineering Department University of Southern California Los Angeles CA 90089 USA HNTB Corporation 200 E Sandpointe Ave #200 Santa AnaCA 92707 USA

Soil-structure interaction （SSI） of a building and shear w.ll above a foundation in an elastic half-space has long been an important research subject for earthquake engineers and strong-motion seismologists. Numerous papers have been published since the early 1970s; how.ver, very few.of these papers have analytic closed-form solu- tions available. The soil-structure interaction problem is one of the most classic problems connecting the tw. dis- ciplines of earthquake engineering and civil engineering. The interaction effect represents the mechanism of energy transfer and dissipation among the elements of the dynamic system, namely the soil subgrade, foundation, and super- structure. This interaction effect is important across many structure, foundation, and subgrade types but is most pro- nounced w.en a rigid superstructure is founded on a rela- tively soft low.r foundation and subgrade. This effect may only be ignored w.en the subgrade is much harder than a flexible superstructure： for instance a flexible moment frame superstructure founded on a thin compacted soil layer on top of very stiff bedrock below. This paper w.ll study the interaction effect of the subgrade and the super- structure. The analytical solution of the interaction of a shear w.ll, flexible-rigid foundation, and an elastic half- space is derived for incident SH w.ves w.th various angles of incidence. It found that the flexible ring （soft layer） cannot be used as an isolation mechanism to decouple asuperstructure from its substructure resting on a shaking half-space.

关键词： Out-of-plane SH w.ves Closed-formanalytic solution Rigid-flexible foundation Fourier-bessel series Soil-structure interaction

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： S.w.w. Y.S.lee Department of Physics and Integrative Institute of Basic Sciences Soongsil University

w. investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4w.re prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show.that the local lattice environment around Eu3+in GdNbO4does not change significantly w.th the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising w.y to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence Sensitizer Rare earths

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)w.th a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,w.re examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy w.s achieved by employing high-ratio differential speed *** best superplasticity w.s achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),w.ere tensile elongations of 550±600%w.re *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size w.s observed at temperatures above 573 ***,it w.s important to consider this effect w.en analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow.at low.strain rates w.s governed by lattice diffusion-controlled grain boundary sliding,w.ile at high strain rates,lattice diffusion-controlled dislocation climb creep w.s the rate-controlling deformation *** w.s concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it w.s observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps w.re constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain grow.h

Nonlinear Characteristic Analysis of Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension System:A Theoretical and Experimental Study

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 338-352页

作者： Xinw.i Jiang Xing Xu Tianling Shi vincent Akolbire Atindana Automotive Engineering Research Institute Jiangsu UniversityZhenjiang 212013China

Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension w.th low.r natural frequencies is w.dely used in commercial vehicle suspension *** ever,traditional pneumatic suspension system is hardly to respond the greatly changed load of commercial vehicles To address this issue,a new.Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension(GIQZSPS)is presented in this paper to improve the vibration isolation performance of commercial vehicle suspension systems under frequent load *** new.structure adds negative stiffness air chambers on traditional pneumatic suspension to reduce the natural frequency of the *** can adapt to different loads and road conditions by adjusting the solenoid valves betw.en the negative stiffness air ***,a nonlinear mechanical model including the dimensionless stiffness characteristic and interconnected pipeline model is derived for GIQZSPS *** the nonlinear mechanical model of GIQZSPS system,the force transmissibility rate is chosen as the evaluation index to analyze ***,a testing bench simulating 1/4 GIQZSPS system is designed,and the testing analysis of the model validation and isolating performance is carried *** results show.that compared to traditional pneumatic suspension,the GIQZSPS designed in the article has a low.r natural *** the system can achieve better vibration isolation performance under different load states by sw.tching the solenoid valves betw.en air chambers.

关键词： Pneumatic suspension Quasi-zero stiffness system Gas-interconnected system Nonlinear dynamic modeling

Evolution of the rare earth trade netw.rk:A perspective of dependency and competition

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Geoscience Frontiers 2024年第3期15卷 183-191页

作者： Jilan Xu Jiahao Li vincent Charles Xin Zhao School of Urban and Regional Science Shanghai University of Finance and EconomicsShanghai 200433China School of Business East China University of Science and TechnologyShanghai 200237China School of Management University of BradfordBradford BD71DPUnited Kingdom School of Statistics and Applied Mathematics Anhui University of Finance and EconomicsBengbu 233030China

As a global strategic reserve resource,rare earth has been w.dely used in important industries,such as military equipment and ***,existing analyses based solely on the total volume of rare earth trade fail to uncover the underlying competition and dependency *** address this gap,this paper employs the principles of trade preference and import similarity to construct dependency and competition *** netw.rk analysis is then employed to study the evolution of the global rare earth trade netw.rk from 2002 to *** main conclusions are as *** global rare earth trade follow. the Pareto principle,and the trade netw.rk show. a scale-free *** has emerged as the w.rld’s largest importer and exporter of rare earth since *** the dependency netw.rk,China has become the most dependent country since *** result of community division show. that China has separated from the American community and formed new.communities w.th the Association of Southeast Asian Nations(ASEAN)*** United States of America has formed a super-strong community w.th European and Asian *** the competition netw.rk,the distribution of competition intensity follow. a scale-free *** countries face low.intensity competition,but there are numerous competing *** competition related to China has increased ***,the competition source for the United States of America has shifted from Mexico to China,resulting in China,the USA,and Japan becoming the core participants in the competition netw.rk.

关键词： Rare earth Trade netw.rk Dependency Competition Complex netw.rk analysis

Reinforcement Learning-Empow.red Graph Convolutional Netw.rk Framew.rk for Data Integrity Attack Detection in Cyber-Physical Systems

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CSEE Journal of Pow.r and Energy Systems 2024年第2期10卷 797-806页

作者： Edeh vincent Mehdi Korki Mehdi Seyedmahmoudian Alex Stojcevski Saad Mekhilef School of Science Computingand Engineering TechnologiesSwinburne University of TechnologyMelbourneAustralia

The massive integration of communication and information technology w.th the large-scale pow.r grid has enhanced the efficiency, safety, and economical operation of cyber-physical systems. How.ver, the open and diversified communication environment of the smart grid is exposed to cyber-attacks. Data integrity attacks that can bypass conventional security techniques have been considered critical threats to the operation of the grid. Current detection techniques cannot learn the dynamic and heterogeneous characteristics of the smart grid and are unable to deal w.th non-euclidean data types. To address the issue, w. propose a novel Deep-Q-Netw.rk scheme empow.red w.th a graph convolutional netw.rk (GCN) framew.rk to detect data integrity attacks in cyber-physical systems. The simulation results show.that the proposed framew.rk is scalable and achieves higher detection accuracy, unlike other benchmark techniques.

关键词： Deep reinforcement learning graph convolutional netw.rk heterogeneous smart grid netw.rk

Anonymity preserving lightw.ight authentication protocol for resource-limited w.reless sensor netw.rks

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High-Confidence Computing 2024年第2期4卷 82-95页

作者： vincent Omollo Nyangaresi Ganesh Keshaorao Yenurkar Jaramogi Oginga Odinga University of Science&Technology BondoKenya Yeshw.ntrao Chavan College of Engineering Wanadongri 441110India

w.reless sensor netw.rks have been deployed in areas such as healthcare,military,transportation and home automation to collect data and forw.rd it to remote users for further *** open w.reless communication channels are utilized for data transmissions,the exchanged messages are vulnerable to various threats such as eavesdropping and message ***,many security solutions have been introduced to address these ***,the resource-constrained nature of the sensor nodes makes it inefficient to deploy the conventional security schemes w.ich require long keys for improved ***,lightw.ight authentication protocols have been ***,majority of these schemes are still insecure w.ile others incur relatively higher energy,computation,communication and storage *** this paper,a protocol that deploys only lightw.ight one-w.y hashing and exclusive OR operations is *** formal security analysis using Real-or Random(ROR)model demonstrates its capability to uphold the security of the derived session *** addition,its semantic security evaluation show. that it offers user privacy,anonymity,untraceability,authentication,session key agreement and key ***,it is show. to resist attacks such as side-channeling,physical capture,eavesdropping,offline guessing,spoofing,passw.rd loss,session key disclosure,forgery and *** terms of performance,it has relatively low.r communication overheads and improves the computation costs and supported security characteristics by 31.56%and 33.33%respectively.

关键词： Anonymity Authentication Formal security Lightw.ight Privacy Sensor w.N

Next generation multiple access for IMT tow.rds 2030 and beyond

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Science China(Information Sciences) 2024年第6期67卷 448-450页

作者： Zhiguo DING Robert SCHOBER Pingzhi FAN H.vincent POOR Department of Computer and Information Engineering Khalifa University Department of Electrical and Electronic Engineering University of Manchester Institute for Digital Communications Friedrich Alexander-University Erlangen-Nurnberg (FAU) CSNMT International Cooperation Research Center (MoST) Southwest Jiaotong University Department of Electrical and Computer Engineering Princeton University

Multiple access techniques are fundamental to the design of w.reless communication systems,since many crucial components of such systems depend on the choice of the multiple access technique[1].For example,the use of ...

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